hello, im building this relay selector circuit, and had a few basic questions

if i want to take the reset function out do i still have to ground pin 15 with the 10k resistor? also would i still need the other 10k resistor next to S1?

im buying all my parts from allelectronics and they don't have the 2N7000 transistor. can you recommend a different transistor that they sale that the CD4017 can drive? here are the relays im going to use. also with the suggested transistor would the 100 ohm resistor be fine?

thank you
seesoe

 

If you remove the switch for reset you should connect pin 15 directly to ground, yes you need the other 10K resistor, it has nothing to do with the reset, and the 2n7000 isn't a transistor, it's a MOSFET.

 

ok, thank you, that's what i was thinking, but wasn't sure.

well a suitable N Channel MOSFET alternative from allelectronics?

thanks
seesoe

 

Any similar N channel FET should do, just look at the datasheet for the 2n7000 and find the voltage and current, then find a fet that's the same or better.

 

im going to go with the BUZ101S

 

If you remove the switch for reset you should connect pin 15 directly to ground, yes you need the other 10K resistor, it has nothing to do with the reset, and the 2n7000 isn't a transistor, it's a MOSFET.

A MOSFET is a Metal-Oxide-Semiconductor Field-Effect Transistor.

 

im going to go with the BUZ101S

BUZ101S won't work with a 5V supply. It requires 10V of gate drive to turn it on. You need a logic level MOSFET, with guaranteed Rds(on) when Vgs>4.5V.
Can't you get 2N7000?
What suppliers are you comfortable with? Maybe we can find a cheap one.

 

oh ok, i just ebayed it and found a nice source. as i have to build 6 of these with a total of 18 transistors, 30 for 5 bucks shipped.

the reason i wanted it from there was because i had a big cart of stuff already, just wanted to make it easier, but i guess not lol

thanks!
seesoe

 

oh ok, i just ebayed it and found a nice source. as i have to build 6 of these with a total of 18 transistors, 30 for 5 bucks shipped.

the reason i wanted it from there was because i had a big cart of stuff already, just wanted to make it easier, but i guess not lol

thanks!
seesoe

There are gobs of 2N7000s on Ebay. I didn't check prices.

 

A MOSFET is a Metal-Oxide-Semiconductor Field-Effect Transistor.

technicalities
Generally transistor refers to a BJT, the annoying current switched things, and mosfet to the awesome voltage switched things.

 

If you like voltage switched things, you should see what vacuum tubes can do!

 

technicalities
Generally transistor refers to a BJT, the annoying current switched things, and mosfet to the awesome voltage switched things.

I guess they must teach things slightly different in the USA to the UK - here a MOSFET is Metal Oxide Silicone Field Effect Transistor. Technicalities !!!

 

technicalities
Generally transistor refers to a BJT, the annoying current switched things, and mosfet to the awesome voltage switched things.

Maybe in your world.
I used to design DRAMs. BJTs were those annoying parasitic structures that caused latchup and subsequent chip damage if you weren't careful in the design phase.